Device for sharpening saws.



'No. 733,636. PATENTED JULY 14, 1903.

G. A. W. & J. H. L. FOLKERS. DEVICE FOR SHARPBNING SAWS.

APPIJOATIOIT FILED OUT. 1, 1902.

H0 MODEL. v 2 SHEETS-:SHBET '1,

A TTORIVEYA' PATENTED JULY 14, 1903.

G. A. W. &-J. H. L. POLKBRS.

DEVICE FOR SHARPENING SAWS.

APPLICATION PILIFD 00121, 1902.

2 SHEETS-SHEET 2.

N0 MODEL WITNESSES: V 0R3 6% Anorlezvzpy UNITED STATES IPatented Jul 14, 1903.

PATENT ()EEIGE.

GEORGE A. W. EoLK Rs AND JOHN H. L. FOLKERS, oE SAN FRANCISCO, CALIFORNIA.

DEVICE FOR SHARPENING SAWS.

SPECIFICATION forming part of Letters Patent No. 733,636, dated July 14, 1903.

Application filed October 1, 1902. Serial No. 125,587. (No model.)

To aZZ whom it may concern.-

Be it known that we, GEORGE A. W. FoL- KERS and JOHN H. L. FOLKERS, citizens of the United States, residing in the city and county of San Francisco, State of California, have invented an Improvement in Devices for Sharpening Saws; and we hereby declare the following to be a full, clear, and exact description of the same.

Our invention relates to improvements in saw filing and sharpening machines of the type employing rotary cutters or grinders. Its object is to provide a sharpener which may be applied to any ordinary saw and which may be held and operated in a uniform relation to the teeth thereof and which shall have its file orgrinding members so disposed as to act upon the teeth to best advantage. It has been customary in devices of this character to dispose the file members in axial alinement, so that they both out directly across the teeth. We have found that by setting these members slightly out of line, but with their axes parallel and in the same horizontal plane and in a way to straddle the teeth, the effect was to draw upward against the teeth edges to be sharpened, causing a steadier and more uniform action,with better result and with a diminution of the disagreeable nerve-racking noise ordinarily accompanying the drawing of a file across the thin edge of a piece of metal.

It consists of the parts and the construction and combination of parts hereinafter to be described, and illustrated by the accompanying drawings, in which- Figure 1 is a side elevation of one form of our device applied to a saw. Fig. 2 is an end elevation of same. Fig. 3 is a plan of the carriage. Fig. 4 (see Sheet 2) is a sectional view of a helical file member. Fig. 5 shows the boxes forming the carriage in position with the file members and driving mechanism omitted. Fig. 6 shows the inner box of the carriage. Fig. 7 shows the outer box. Fig. 8 is a guide-stirrup for alining the saw in the vise. Fig. 9 is a side view of our second form of device for saw-sharpening. Fig. 10 is an end view, and Fig. 11 is a top view, of the same. Fig. 12'is a perspective view of one of our cutters.

Having reference to Figs. 1 to 8, inclusive, which show one form of our machine, A represents a vise or holder in which the saw 2 is adapted to be clamped and held by means of the pivoted arm 3 and eccentric 1. The rigid members of the vise between which the saw is held have each a horizontal track or guide 5 secured to them, on which the file-carriage may travel the lengthof the saw. This carriage consists of two telescoping frames or boxes 6 and '7, the outer of which, 6, has the lateral guides 8, whichare adapted to embrace the traoks 5.. Adjusting-screws 9 on either side of the carriage allow of a lateral adjustment of the latter in relation to the saw. A hearing plate or bar 10 is interposed between the ends of the screws and each of the tracks, so as to insure the carriage a free sliding movement. The opposite side walls of the outer carriage-box are cut away, as shown, so as to leave projections 11, having beveled vertical edges. The corresponding walls of the inner box are cut away to form the complementary slots 12, in which the projections 11 are slidable. These boxes thus have a snug fit, one within the other,--and are guided truly in their relative vertical adjustment, and all possibility oflateraldisplacementis obviated. This vertical adjustment is effected by means of'the adjusting jack-screws 13, which have their ends suitably seated in the projection or lugs 14 on each box. The file members or grinders 15 15 are journaled in the inner box, one oneach side of a line extending lengthwise and centrally of the box. Power is transmitted from a hand-wheel 16 to rotate the members in 0pposite directions through a suitablebevel-gear 17, engaging a corresponding gear 18 on the end of the shaft of rotary member 15. 'This shaft carries a gear 19, meshing a gear 20 on the shaft of-member 15. The file members have helical ribs with beveled abrading-suw faces to correspond to the de'sired 'pitch of the saw-teeth to be sharpened. Heretofore it has been customary to form these ribs with their interspaces V-shaped' T Fig. 4 shows a preferred shape for'the ribs, in which the interspaces 21-are formed rectangular in cross-section, so that greater a ccommodation is olfered for the saw-teeth and all danger of the teeth-points striking the bottom of the groove is obviated even after the grinders have become considerably worn.

In order to avoid unnecessary vibration o; the parts and the possible ripping or mutilation of the teeth when the grinders first engage the teeth at the end of the saw, the grinders are made with the first turn of the ribs blank, as shown in Fig. 12. This blank portion 21 forms a guide or lead for the easy and gradual feed of the grinders into the teeth. The distance between the adjacent abradingsurfaces of these ribs is such that two teeth will be accommodated in each interspaoe, and each member is adapted to sharpen the teeth skipped by the other member. It is our intention to make these grinders of mineral compounds commercially known as oorundnm, carborundum, &c.

In operation a saw is placed in the vise and beneath the carriage and securely clamped therein by means of the arm 3 and eccentric or cam t and with the points of the saw-teeth in a line parallel with tracks 5. The carriage is then adjusted laterally by means of the set-screws 9 till the plane of the saw bisects the angle formed between the curved planes of the peripheries of the file members. The file-carriage 7 is then vertically adjusted by means of the screws 13, according to the desired depth of the interdental out. By turning the crank-wheel 16 the grinders are rotated so that each cuts upwardly on the teeth and in a line diagonally to the vertical plane of the saw. The result is a minimum amount of vibration and the teeth are sharpened uniformly and rapidly according as the machine is advanced from one end of the saw to the other. A guide or stirrup 22 may be used to insure properalinement of the saw-teeth when the saw is placed in the vise. In operation one of these stirrups is slipped on at each end of the track. The lower edge of the transverse portion of the stirrups is approximately in the same plane with the imaginary line of intersection of the peripheries of the file members. hen the saw is brought up against these guides 22, it will lie in proper relation to the file-carriage, so that the latter may travel over it to engage the saw-teeth.

In Fig. 9 is shown a vertical arrangement of our device in which the file-carriage 7 is stationary, while the saw-carrying means A travels downward by gravity and the action of the rotating grinders. The file-support in this case simply consists of a casting secured rigidly to the wall, having a suitable opening 23 to accommodate the saw-carriage or vise A, and the grinders 15 15, disposed in suitable relation to the path of the saw, are similar in construction, operation, and principle with those described in connection with Fig. l. The saw is clamped in vise A by suitable means, as the arm 3 and eccentric 4L, and the back of the saw is supported to bring the teeth in proper relation to the grinders by means of the stirrups 24 and adjusting-screws 25. The tracks or guides of the saw-carriage are united at the ends to, inclose the saw-space, and they are supported in the guide-grooves 26 in casting 7. Screws 9 and suitable bearing plates or rollers 10 allow of the proper lateral adjustment of the tracks. By turning the crank 16 the grinders are rotated and act upon the saw-teeth to sharpen them and at the same time act to draw the saw downward. The downward feed of the saw, assisted by gravity, as it is, tends to a more even out than where the saw is disposed horizontally, and the advance of the saw or of the file-carriage is dependent on the friction of the grinders on the teeth alone. In the latter case it has been found in some instances that the back pressure of the grinders wore the teeth away more rapidly on the front than on the rear edges.

Having thus described our invention, what we claim, and desire to secure by Letters Patent, is

1. The combination in a saw-sharpening device, of saw-holding means, helical file members disposed one behind the other but slightly out of axial alinement and arranged to act upon opposite sides of the teeth simultaneonsly in a direction diagonal to the vertical plane of the saw, and means for rotating the file members.

2. The combination in a saw-sharpening device, of sawholding means, rotary file members disposed one behind the other but slightly out of axial alinement, and arranged to act upon opposite sides of the saw simultaneously, and means for rotating the file members in unison.

3. In a device of the character described, the combination of rotary helical file members; a file-carriage and saw-carrying means said carriage and file members vertically disposed and movable by gravity one relative to the other.

4. In a device of the character described, the combination of a stationary file-carriage; rotary file members therein; and a verticallyextending saw-carriage mounted in the filecarriage and adapted to travel downward therein by gravity and the action of the file members.

5. In a device of the character described, the combination of rotary helical file members disposed one behind the other but out of axial alinement, a stationary support for said members and a movable gravity-actuated saw-support.

In witness whereof we have hereunto set our hands.

GEORGE A. W. FOLKERS. JOHN H. L. FOLKERS. Witnesses:

S. 1'1. N OURSE, JESSIE O. BRODIE. 

